void setup() {
  pinMode(13, OUTPUT);
}

void loop() {
  int red = 13, yellow = 12, green = 11;
  digitalWrite(red, HIGH);
  // digitalWrite(yellow, LOW);
  // digitalWrite(green, LOW);
  // delay(3000);
  // digitalWrite(red, LOW);
  digitalWrite(yellow, HIGH);
  // digitalWrite(green, LOW);
  // delay(1000);
  // digitalWrite(red, LOW);
  // digitalWrite(yellow, LOW);
  digitalWrite(green, HIGH);
  // delay(3000);
}